Visible-light-induced 1,3-difunctionalization of allylboronic esters enabled by a 1,2-boron shift†

Abstract

A novel visible-light-induced strategy has been developed for 1,2-boron migration to achieve 1,3-difunctionalization of allylboronic esters using vinyl triflates as bifunctional reagents. This approach demonstrates significant atomic and step economy, allowing for the construction of two C–C bonds and one C–B bond in a single preparative step under mild reaction conditions. This methodology enables the conversion of a wide array of natural products and pharmacologically relevant molecules, achieving satisfactory yields. Furthermore, this protocol is also successfully extended to other bifunctional reagents, such as tosylates and benzenesulfonyl cyanide, affording the corresponding sulfonyl products in good yields. Given the importance of boron and cyano functionalities in organic synthesis, these products hold considerable promise as intermediates for the synthesis of alcohols or amides. A comprehensive investigation of the reaction mechanism was performed, utilizing radical capture experiments, Stern–Volmer fluorescence quenching, cyclic voltammetry, light on–off experiments, and quantum yield measurements to elucidate the underlying processes involved.